In the New Layer window, set a unique name for the new channel (ZDepth). The channel names are very important in Nuke. It is necessary to avoid duplication, so give them meaningful names so that you can find them easily. Click on the rgba below Auto. In the Channels lines will appear: red, green, blue, alpha etc. Erase all except the red one. In the settings tab of the ShuffleCopy node, put crosses in according to the scheme shown in Fig.34.

Fig.34

The logic is that we have rgb (Pontiac) in the second channel, and in the first channel we have a black and white map of the depth of the scene (ZDepth). The depth channel is transferred into the red channel and is added to the basic rgb channels.

And now in the Viewer tab from the drop-down menu besides rgb we also have a ZDepth channel (Fig.35).

Fig.35

Now we can add a ZBlur node, by going to Filter > ZBlur, and get the effect of blur depth (Fig.36).

Fig.36

We can see that the whole scene is now blurry. We need to set the channel, which will be a basis for blurring, by selecting from the drop-down list. We use ZDepth.red. Activate the focal-plane setup; it will help us to understand where the image will become sharp and where blurry. The viewer will turned blue (Fig.37).